JP3070547B2 - Valve timing control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for adjusting the opening / closing timing (valve timing) of an intake valve or an exhaust valve according to the operating conditions of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a mechanism disclosed in Japanese Patent Application Laid-Open No. 9-60508 is known as a mechanism for variably controlling the valve timing of an intake valve and / or an exhaust valve in accordance with an operation state. As a method of controlling the mechanism, for example, a method disclosed in Japanese Patent Application Laid-Open No. H6-159021 is known. Hereinafter, a conventional valve timing control device for an internal combustion engine will be described with reference to FIGS. 22 to 27 according to a conventional device and FIGS. 2 to 1 according to an embodiment of the present invention.
3 will be described.

FIG. 2 is a schematic diagram showing a gasoline engine system having a variable valve timing mechanism. In FIG. 2, reference numeral 1 denotes an engine constituted by a plurality of cylinders, for example, four cylinders, each of which is illustrated for one cylinder; 2, a cylinder block forming a plurality of cylinders of the engine 1; The cylinder head 4 is a piston that reciprocates up and down in each cylinder of the cylinder block 2. Also,
Reference numeral 5 denotes a crankshaft connected to the lower end of the piston 4. The crankshaft 5 is rotated by moving the piston 4 up and down.

A crank angle sensor 6 is disposed near the crankshaft 5 for detecting the rotational speed NE of the engine 1 and whether the crankshaft 5 is at a predetermined reference crank angle. Is connected to the signal rotor. This signal rotor 7
Are formed on the outer circumference at every 180 °, and each time these teeth pass in front of the crank angle sensor 6, the crank angle sensor 6 generates a pulse-like crank angle signal.

[0005] A combustion chamber 8 is formed by the inner wall of the cylinder block 2 and the cylinder head 3 and a top of the piston 4 for burning an air-fuel mixture. A combustion chamber 8 is provided at the top of the cylinder head 3. A spark plug 10 for igniting the air-fuel mixture is disposed so as to protrude from the cylinder head 3, a distributor connected to an exhaust-side camshaft 20 (described later) of the cylinder head 3, and 11 generates a high voltage. Igniter. Each spark plug 9 is connected to a distributor 10 via a high-voltage cord (not shown). The high voltage output from the igniter 11 is applied to each spark plug 9 by the distributor 10 in synchronization with the rotation of the crankshaft 5. Be distributed.

Reference numeral 12 denotes a water temperature sensor disposed on the cylinder block 2 for detecting the temperature (cooling water temperature) THW of the cooling water flowing through the cooling water passage. Reference numeral 13 denotes an intake port provided in the cylinder head 3, reference numeral 14 denotes an exhaust port provided in the cylinder head 3, reference numeral 15 denotes an intake passage connected to the intake port 13, and reference numeral 16 denotes an exhaust passage connected to the exhaust port 14. Reference numeral 17 denotes an intake valve disposed at the intake port 13 of the cylinder head 3, and reference numeral 18 denotes an exhaust valve disposed at the exhaust port 14 of the cylinder head 3.

[0007] 19 is disposed above the intake valve 17,
An intake camshaft 20 for opening and closing the intake valve 17 is disposed above the exhaust valve 18, and is an exhaust camshaft for opening and closing the exhaust valve 18. Further, 21 is an intake-side timing pulley attached to one end of the intake-side camshaft 19, 22 is an exhaust-side timing pulley attached to one end of the exhaust-side camshaft 20,
Reference numeral 23 denotes a timing belt that connects each of the timing pulleys 21 and 22 to the crankshaft 5. The intake camshaft 19 and the exhaust camshaft 20 rotate at half the speed of the crankshaft 5.

Accordingly, when the engine 1 is operated, a rotational driving force is transmitted from the crankshaft 5 to the respective camshafts 19, 20 via the timing belt 23 and the respective timing pulleys 21, 22, and the respective camshafts 19, 20 rotate. The intake valve 17 and the exhaust valve 18
Is driven to open and close. These valves 17 and 18 are synchronized with the rotation of the crankshaft 5 and the vertical movement of the piston 4, that is, the intake stroke, the compression stroke, the explosion / expansion stroke,
The engine 1 is driven at a predetermined opening / closing timing in synchronization with a series of four strokes of the engine 1 including an exhaust stroke.

Further, reference numeral 24 denotes a cam angle sensor disposed near the intake camshaft 19 for detecting the valve timing of the intake valve 17, and 25 denotes a signal rotor connected to the intake camshaft 19. is there. Four teeth are formed on the outer periphery of the signal rotor 25 at every 90 °. Each time these teeth pass in front of the cam angle sensor 24, a pulse-like cam angle signal is generated from the cam angle sensor 24. I do.

Reference numeral 26 denotes a throttle valve arranged in the middle of the intake passage 15 and driven to open and close in conjunction with an accelerator pedal (not shown). The throttle valve 26 is opened and closed to adjust the amount of intake air. Is done. 27 is connected to the throttle valve 26 and disposed.
Throttle sensor for detecting the throttle opening TVO, 2
Reference numeral 8 denotes a thermal intake air amount sensor which is disposed upstream of the throttle valve 26 and detects an air flow rate (intake air amount) QA to be taken into the engine 1. Reference numeral 29 denotes a throttle valve 2
A surge tank 30 formed on the downstream side of the cylinder 6 for suppressing intake pulsation is disposed near each intake port 13 of each cylinder, and is an injector for supplying fuel to the combustion chamber 8.

Each injector 30 is an electromagnetic valve that is opened by energization, and each injector 30 is supplied with fuel pumped from a fuel pump (not shown). Therefore, when the engine 1 is operating, air is taken into the intake passage 15, and fuel is injected from each injector 30 toward the intake port 13 at the same time as taking in the air.
As a result, an air-fuel mixture is generated at the intake port 13, and the air-fuel mixture is sucked into the combustion chamber 8 with the opening of the intake valve 17 that is opened during the intake stroke.

Reference numeral 40 denotes a valve timing variable mechanism (hereinafter referred to as VVT) which is disposed in connection with the intake side camshaft 19 and is driven by lubricating oil of the engine 1 as hydraulic oil to change the valve timing of the intake valve 17. ). The VVT 40 changes the valve timing of the intake valve 17 continuously by changing the displacement angle of the intake camshaft 19 with respect to the intake timing pulley 21. Reference numeral 80 denotes an oil control valve (hereinafter, referred to as OCV) that supplies hydraulic oil to the VVT 40 and adjusts the oil amount.

100 is an electronic control unit (hereinafter referred to as EC)
U), based on signals from the intake air amount sensor 28, the throttle sensor 27, the water temperature sensor 12, the crank angle sensor 6, and the cam angle sensor 24.
0, the igniter 11 and the OCV 80 are driven to control the fuel injection amount, ignition timing, and valve timing.

Next, the configuration of a variable valve timing system using the VVT 40 and the OCV 80 will be described with reference to FIGS. Here, FIG. 3 is a sectional view of the vicinity of the intake side camshaft 19 where the VVT 40 is disposed, and FIG.
FIG. 4 is an explanatory diagram showing a configuration of a hydraulic oil supply unit for driving a VT 40.

In FIG. 3, reference numeral 40 denotes a VVT for adjusting the intake valve timing. Reference numeral 21 denotes an intake-side timing pulley that rotates in synchronization with the crankshaft 5 when a timing belt 23 rotated by the crankshaft 5 is hung. 19 is
The intake camshaft is connected to the VVT 40 and transmitted with the phase of the rotation of the intake timing pulley 21 changed through the VVT 40. Reference numeral 41 denotes a bearing which rotatably supports the intake side camshaft 19 and is fixed to the cylinder head 3. Reference numeral 42 denotes a first oil passage which is provided on the intake side camshaft 19 and the rotor 52 (described later) and communicates with a retard hydraulic chamber 62 (described later) for moving the rotor 52 in the retard direction. 43 is the intake side camshaft 19
And a second oil passage provided in the rotor 52 (described later) and communicating with an advanced hydraulic chamber 63 (described later) that moves the rotor 52 (described later) in the advanced direction.

Reference numeral 80 denotes an OCV for controlling the amount of hydraulic oil supplied to the VVT 40. Reference numeral 90 denotes an oil pan provided in the engine 1, reference numeral 91 denotes an oil pump, and reference numeral 92 denotes an oil filter. The oil pan 90, the oil pump 91, and the oil filter 92 constitute a lubricating device for lubricating each part of the engine 1. With OCV80
Together, they constitute a hydraulic oil supply device to the VVT 40.

Here, 81 is a housing, 82 is a spool valve that slides inside the housing 81, 83 is an ECU 100
Is a linear solenoid that slides the spool valve 82 in accordance with the control signal from the controller, and 84 is a spring that biases the spool valve 82 in a direction opposite to the driving direction of the linear solenoid 83. Reference numeral 85 denotes a supply port formed in the housing 81 and communicated with the oil pump 91 via an oil filter 92, 86 denotes an A port formed in the housing 81, and A port communicates with the first oil passage 42, and 87 denotes a housing 81. B ports 88a and 8 communicated with the second oil passage 43
8b is a discharge port formed in the housing 81 and communicated with the oil pan 90.

The operation of the oil pump 91 in conjunction with the rotation of the crankshaft 5 of the engine 1 causes the hydraulic oil sucked up from the oil pan 90 to flow through the oil pump 9.
1 is discharged. The discharged hydraulic oil passes through the oil filter 92 and is selectively pumped to the oil passages 42 and 43 by the OCV 80. The amount of oil in each of the oil passages 42 and 43 is increased or decreased as the spool valve 82 slides and the opening of each of the A port 86 and the B port 87 is continuously changed. Is determined by the value of the current supplied to. The ECU 100 controls a current supplied to the linear solenoid 83 based on various sensor signals from the crank angle sensor 6, the cam angle sensor 24, and the like.

Further, reference numeral 44 denotes an intake side camshaft 19.
The housing is rotatably arranged with respect to the housing. 45
Is a case fixed to the housing 44. 46
Is a leaf spring type back spring that is installed between the chip seal 49 (described later) and the case 45 and presses the chip seal 49 against the rotor 52 (described later). 47 is a cover fixed to the case 45. 48 is a bolt for fixing the housing 44, the case 45 and the cover 47. Reference numeral 49 denotes a tip seal which is pressed against the rotor 52 by the back spring 46 and prevents movement of hydraulic oil between the hydraulic chamber partitioned by the rotor 52 and the case 45. 50 is a plate attached to the cover 47. Reference numeral 51 denotes a screw for fixing the plate 50 to the cover 47.

Reference numeral 52 denotes a rotor fixed to the intake camshaft 19 and rotatably disposed relative to the case 45. Reference numeral 53 denotes a cylindrical holder provided on the rotor 52 and having a concave portion that engages with a plunger 54 (described later). The housing 44 is formed by the elasticity of a spring 55 (described later) and the hydraulic pressure introduced into the holder 53.
It is a plunger as a convex member that slides inside. 55
Is a spring for urging the plunger 54 in the direction of the rotor 52. Reference numeral 56 denotes a plunger oil passage for introducing a hydraulic pressure for applying a hydraulic pressure against the urging force of the spring 55 to the plunger 54. Reference numeral 57 denotes an air hole for constantly setting the spring 55 side of the plunger 54 to atmospheric pressure.

Reference numeral 58 denotes a connection bolt for connecting and fixing the intake side camshaft 19 and the rotor 52. 59
Is a shaft bolt for connecting and fixing the intake side camshaft 19 and the rotor 52 on the rotation axis thereof. The shaft bolt 59 is provided rotatably with respect to the cover 47. Reference numeral 60 denotes an air hole provided in the shaft bolt 59 and the intake side camshaft 19 to make the inside of the plate 50 the same pressure as the atmospheric pressure.

FIG. 4 is an explanatory view showing a state in which hydraulic pressure is applied to the plunger 54 via the plunger oil passage 56. As shown in this figure, the plunger 54 is pressed against the housing 44 by compressing the spring 55 by hydraulic pressure, the engagement with the holder 53 is released, and the rotor 52 can rotate with respect to the housing 44. can do.

FIG. 5 is an explanatory view of the section taken along line XX in FIG. 3 as viewed from the direction of the arrow, FIG. 6 is an explanatory view showing the moving state of the slide plate 71, and FIG. YY
FIG. 8 is an explanatory diagram of the cross section as viewed from the direction of the arrow, and FIG. 8 is an explanatory diagram of the ZZ cross section in FIG. 3 as viewed from the direction of the arrow.

In these figures, reference numeral 61 denotes a bolt 48
Are bolt holes to be screwed. Reference numeral 62 denotes a fan-shaped retard hydraulic chamber for rotating the first to fourth vanes 64 to 67 (described later) in the retard direction.
The rotor 5 corresponds to each of the fourth vanes 64 to 67.
2, a case 45, a cover 47, and a housing 44. The retard hydraulic chamber 62 is provided with a first
The first oil passage 42 communicates with the oil passage 42 to supply hydraulic oil.

Reference numeral 63 denotes a fan-shaped advance hydraulic chamber for rotating the first to fourth vanes 64 to 67 in the advance direction.
The advance hydraulic chamber 63 corresponds to each of the first to fourth vanes 64 to 67, and corresponds to the rotor 52, the case 45, and the cover 4.
7. It is provided so as to be surrounded by the housing 44. Also,
The advancing hydraulic chamber 63 communicates with the second oil passage 43, and hydraulic oil is supplied from the second oil passage 43. The rotor 52 moves relative to the housing 44 in accordance with the amount of hydraulic oil supplied to the retard hydraulic chamber 62 and the advance hydraulic chamber 63, and the volume of each hydraulic chamber changes.

Reference numeral 64 denotes a first vane protruding from the rotor 52 in the outer diameter direction. A holder 53 is fitted into the first vane 64 on the housing 44 side, and a cover 4 is provided.
A communication oil passage 70 (described later) is recessed on the side 7, and a moving groove 72 (described later) is recessed in the middle of the communication passage 70, and the housing 53 passes through the holder 53 from the moving groove 72. A plunger oil passage 56 is penetrated to the 44 side.

Reference numerals 65 to 67 denote second to fourth vanes projecting from the rotor 52 in the outer diameter direction, respectively. Further, tip seals 73 (described later) are provided at portions of the first to fourth vanes 64 to 67 that come into contact with the case 45. Reference numeral 68 denotes a vane support which is a central portion of the rotor 52. 69 is a shoe protruding in the radial direction from the case 45. The shoe 69 is provided with a bolt hole 61 into which the bolt 48 is inserted, and a chip abutting on the vane support 68 is provided with a chip. A seal 49 is provided.

Reference numeral 70 denotes a communication oil passage which connects the retard hydraulic chamber 62 and the advance hydraulic chamber 63 on both sides of the first vane 64.
71 is a moving groove 72 provided in the middle of the communication oil passage 70.
The communication passage 70 is disconnected by the slide plate 71 so that no oil leaks between the retard hydraulic chamber 62 and the advance hydraulic chamber 63. Have been. When the hydraulic pressure of the retard hydraulic chamber 62 is high, the slide plate 71
As shown in FIG. 5, it moves to the advance hydraulic chamber 63 side, and when the hydraulic pressure in the advance hydraulic chamber 63 is high, it moves to the retard hydraulic chamber 62 side as shown in FIG.

Reference numeral 72 denotes a moving groove formed in the middle of the communication oil passage 70, and the plunger oil passage 56 communicates with the movement groove 72. Here, the slide plate 71
However, as shown in FIG. 5, when the plunger oil passage 56 is moved to the advance hydraulic chamber 63 side, the plunger oil passage 56 communicates with the retard hydraulic chamber 62, and the slide plate 71 is shown in FIG. As described above, when the plunger oil passage 56 moves toward the retard hydraulic chamber 62, the plunger oil passage 56 communicates with the advance hydraulic chamber 63. 7
Reference numeral 3 denotes a chip seal provided on each of the first to fourth vanes 64 to 67 to seal between the vanes and the case 45 to prevent oil leakage. Arrows in FIGS. 5, 7, and 8 indicate VVT by the timing belt 23 or the like.
The rotation direction of the whole 40 is shown.

Next, the operation of the VVT 40 and the OCV 80 will be described. First, in a state where the engine 1 is stopped, the position of the rotor 52 is set to the maximum retarded position as shown in FIG. The oil pressure supplied from the oil pump 91 to the OCV 80 is low, or
At atmospheric pressure, no oil pressure is supplied to the first and second oil passages 42 and 43, and therefore no oil pressure is supplied to the plunger oil passage 56. Therefore, as shown in FIG.
The plunger 54 and the holder 53 are engaged with each other by the urging force of the spring 55.

Next, when the engine 1 is started, the oil pump 91 operates, the hydraulic pressure supplied to the OCV 80 increases, and the hydraulic pressure is supplied to the retard hydraulic chamber 62 via the A port 86. At this time, the slide plate 71 moves to the advance hydraulic chamber 63 side by the hydraulic pressure of the retard hydraulic chamber 62, the retard hydraulic chamber 62 communicates with the plunger oil passage 56, and the plunger 54 is pressed, and It moves to the 44 side, and the engagement between the plunger 54 and the rotor 52 is released. However, since the hydraulic pressure is supplied to the retard hydraulic chamber 63, each of the vanes 64-67 is in contact with and pressed against the shoe 69 in the retard direction, and the engagement by the plunger 54 is released. The housing 44 and the rotor 52 are pressed against each other by the hydraulic pressure of the retard hydraulic chamber 62, so that vibration and impact can be reduced or eliminated.

Next, in order to advance the rotor 52, B
When the port 87 is opened, hydraulic oil is supplied to the advance hydraulic chamber 63 via the second oil passage 43. Then, the hydraulic pressure is transmitted from the advance hydraulic chamber 63 to the communication oil passage 70, the slide plate 71 is pressed by the hydraulic pressure, and moves to the retard hydraulic chamber 62 side. By the movement of the slide plate 71, the plunger oil passage 56 communicates with the advance hydraulic chamber 63 of the communication oil passage 70, and hydraulic pressure is transmitted from the advance hydraulic chamber 63 to the plunger oil passage 56. As shown in (5), the plunger 54 moves toward the housing 44 against the urging force of the spring 55, and the engagement between the plunger 54 and the holder 53 is released. By adjusting the supply oil amount by opening and closing the A port 86 and the B port 87 in a state where the engagement between the plunger 54 and the holder 53 is released, the retard hydraulic chamber 6 is controlled.
2. By adjusting the amount of oil in the advance hydraulic chamber 63, the rotation of the rotor 52 can be advanced or retarded with respect to the rotation of the housing 44.

Hereinafter, a typical operation state of the OCV 80 will be described with reference to FIG. FIG. 9A shows an example in which the control current value from the ECU 100 is 0.1 A, which is smaller than the reference value 0.5 A. The spool valve 82 is urged to the left end of the housing 81 by the spring 84 to supply the supply port. 85-
Between A port 86, and B port 87-discharge port 88b
This shows a state in which the spaces communicate with each other. At this time, while hydraulic oil is supplied to the retard hydraulic chamber 62 and hydraulic oil is discharged from the advance hydraulic chamber 63, the rotor 52 shown in FIG. Rotating, the intake side camshaft 1 with respect to the intake side timing pulley 21
The phase of No. 9 is delayed, and the retard control is performed.

FIG. 9B shows an example in which the control current value from the ECU 100 is 0.5 A, which is the reference value.
When the opposing forces of the linear solenoid 83 and the spring 84 are balanced, the spool valve 82 is maintained at a position where both the A port 86 and the B port 87 are closed, and the retard hydraulic chamber 62 and the advance hydraulic chamber 63 operate. This shows a state where oil supply and discharge are not performed. At this time, if there is no leakage of hydraulic oil from the retard hydraulic chamber 62 and the advance hydraulic chamber 63, the rotor 52 is held at the current position, and the phases of the intake-side timing pulley 21 and the intake-side camshaft 19 are Will be maintained.

FIG. 9C shows an example in which the control current value from the ECU 100 is 1.0 A, which is larger than the reference value 0.5 A, and the spool valve 82 has a linear solenoid 83
Is driven to the right end of the housing 81 by the
5-B port 87, and A port 86-discharge port 8
8a shows a state in which communication is established. At this time, hydraulic oil is supplied to the advance hydraulic chamber 63 through the second oil passage 43, while hydraulic oil is discharged from the retard hydraulic chamber 62.
Accordingly, the rotor 52 shown in FIG. 9 rotates clockwise with respect to the housing 44, and the phase of the intake camshaft 19 with respect to the intake timing pulley 21 advances, so that the advance control is performed.

9 (a), 9 (b) and 9 (c), the supply port 85 and the A port 86 (or the B port 8)
7) Communication and discharge port 88b (or 88a) during
The communication between the port 82 and the B port 87 (or the A port 86) is controlled by the position of the spool 82. Further, the position of the spool valve 82 and the current value of the linear solenoid 83 are in a proportional relationship. FIG. 10 is a characteristic diagram illustrating a relationship between a current value of the linear solenoid 83 (hereinafter, referred to as a linear solenoid current) under an operating condition of the engine 1 and an actual valve timing change speed. In FIG. 10, the region where the actual valve timing change speed is positive corresponds to the region moving in the advance direction, while the region where the actual valve timing change speed is negative corresponds to the region moving in the retard direction. Equivalent to.

In FIG. 10, each symbol (a),
(B) and (c) show the linear solenoid current corresponding to each position of the spool valve 82 in FIGS. 9 (a), (b) and (c), respectively. The linear solenoid current whose actual valve timing does not change as indicated by the symbol (b) is the amount of hydraulic oil leaking from each of the hydraulic chambers 62 and 63, the hydraulic piping, and the spool valve 82, and the amount of hydraulic oil pumped from the oil pump 91. There is only one point to balance with.

Further, this point always fluctuates because the characteristic changes as shown in FIG. 11 due to the fluctuation of the hydraulic oil discharge pressure due to the engine speed and temperature. Further, this point and the manner of changing the characteristics differ depending on the product due to product variations such as the dimensions of the spool valve 82. The linear solenoid current at the point where the actual valve timing does not change is hereinafter referred to as a holding current, and is represented by a symbol HLD. The control can be performed by increasing the linear solenoid current when the valve timing is to be advanced based on the holding current HLD, and by decreasing the linear solenoid current when the valve timing is to be retarded based on the holding current HLD.

Next, a method of detecting valve timing is shown in FIG.
2 will be described. FIG. 12A shows a crank angle signal, and FIG. 12B shows a cam angle signal at the most retarded angle.
(C) is a timing chart showing a cam angle signal at the time of advance. The ECU 100 measures the crank angle signal period T and the phase difference time TVT from the cam angle signal to the crank angle signal, and determines the most significant value from the phase difference time TVT0 and the crank angle signal period T when the valve timing is in the most retarded state. The retard valve timing VTR is obtained according to the equation (1) and stored.

[0040]

(Equation 1)

The actual valve timing VTA is obtained from the phase difference time TVT, the crank angle signal cycle T and the most retarded valve timing VTR according to the equation (2).

[0042]

(Equation 2)

The ECU 100 calculates the difference between the actual valve timing VTA and the target valve timing VTT based on the deviation.
The actual valve timing VTA converges to the target valve timing VTT by performing feedback control of the linear solenoid current.

FIG. 13 is an explanatory diagram showing the internal configuration of the ECU 100. In FIG. 13, reference numeral 101 denotes a microcomputer, which is a central processing unit (CPU) 102 that performs various calculations and determinations, a read-only memory (ROM) 103 that stores a predetermined control program and the like in advance, and temporarily stores calculation results of the CPU. Random access memory (RA
M) 104, A / which converts an analog voltage into a digital value
A D converter 105, a counter 106 for measuring the cycle of the input signal, etc., and a timer 10 for measuring the drive time of the output signal, etc.
7, an output port 108 for outputting an output signal, and a common bus 109 for connecting these.

Reference numeral 110 denotes a first input circuit. The signal from the cam angle sensor 24 is shaped by the first input circuit 110 and input to the microcomputer 101 as an interrupt command signal (INT). Every time this interrupt is issued, the CPU 102 reads the value of the counter 106 and stores it in the RAM 104. The signal from the crank angle sensor 6 is shaped by the first input circuit 110 and input to the microcomputer 101 as an interrupt command signal (INT). Every time this interrupt is issued, the CPU 102 reads the value of the counter 106 and
AM 104, the crank angle signal period T is calculated from the difference from the counter value when the signal from the crank angle sensor 6 was previously input, and the crank angle signal period T
The engine speed NE is calculated based on the following. Also, RAM
From the difference from the counter value when the signal from the cam angle sensor 24 stored in 104 is input, the phase difference time TV
Calculate T.

Reference numeral 111 denotes a second input circuit. Water temperature sensor 12, throttle sensor 27, intake air amount sensor 28
Is removed or amplified by the second input circuit 111 to provide a signal to the A / D converter 105.
Here, it is converted into digital data of the cooling water temperature THW, the throttle opening TVO, and the intake air amount QA.

Reference numeral 112 denotes a drive circuit for driving the injector 30, and reference numeral 113 denotes a drive circuit for driving the igniter. The CPU 102 calculates the injector driving time and the ignition timing based on the various input signals, and drives the injector 30 and the igniter 11 through the output port 108 and the driving circuits 112 and 113 based on the time measurement result of the timer 107. And fuel injection amount control,
Perform ignition timing control.

Reference numeral 114 denotes a current control circuit for controlling the linear solenoid current of the OCV 80. CPU10
2 calculates the linear solenoid current CNT of the OCV 80 based on the various input signals, and outputs a duty signal corresponding to the linear solenoid current CNT of the OCV 80 to the output port 108 based on the time measurement result of the timer 107. The current control circuit 114 performs valve timing control based on the duty signal by controlling the current flowing through the linear solenoid 83 of the OCV 80 to be the linear solenoid current CNT.

Reference numeral 115 denotes a power supply circuit, 116 denotes a battery,
Reference numeral 17 denotes a key switch, and the microcomputer 10
1 operates by receiving a constant voltage from the power supply circuit 115 to which the voltage of the battery 116 is input via the key switch 117.

Next, the operation of the CPU 102 will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 22 is an operation timing diagram when the actual holding current HLD matches the reference value 0.5 A in the control device without the integration control means. FIG. 23 is a control device without the integration control means.
FIG. 24 is an operation timing diagram when the actual holding current HLD is shifted to a higher current side than the reference value 0.5 A. FIG. 24 shows the actual holding current HL in the control device having the integration control means.
FIG. 9 is an operation timing chart when D is shifted to a higher current side than a reference value of 0.5 A.

The OCV 80 can adjust the amount of supplied hydraulic oil per unit time, and the VVT 40 determines the displacement angle corresponding to the integrated amount of supplied hydraulic oil. In this sense, since the VVT 40 to be controlled includes an integral element, the OCV
Assuming that the actual holding current HLD at 80 matches the reference value 0.5A, the control means responds to the deviation ER between the target valve timing VTT and the actual valve timing VTA based on the reference value 0.5A. By performing proportional control,
The actual valve timing can be made to converge to the target valve timing. At this time, the linear solenoid current CNT of the OCV 80 is given by Expression 3.

[0052]

(Equation 3)

In the equation (3), ER is a deviation between the target valve timing VTT and the actual valve timing VTA, and is calculated as in the equation (4).

[0054]

(Equation 4)

In the equation (3), KP is a gain corresponding to the proportional operation. FIG. 22 shows the movements of the target valve timing VTT, the actual valve timing VTA, and the linear solenoid current CNT at this time.

However, the actual holding current HL of the OCV 80
D does not always match the reference value 0.5A. For example, when the actual holding current HLD is shifted to a higher current side than the reference value 0.5 A, if the control based on the equation (3) is performed, as shown in FIG.
A does not converge to the target valve timing VTT, and a steady-state error ER1 remains. That is, the control device sets the deviation ER between the target valve timing VTT and the actual valve timing VTA to 0.
The linear solenoid current CNT of the OCV 80 is controlled so that In the case of FIG. 23, since the deviation remains by ER1, (KP × ER1 + 0.5) A is given as the linear solenoid current CNT in order to make it zero. However, in FIG. 23, the actual holding current HLD is shifted to a higher current side by (KP × ER1) than the reference value 0.5A. Therefore, the control device intends to control the actual valve timing VTA to converge to the target valve timing VTT by applying a current higher than the reference value 0.5A by (KP × ER1) to eliminate the deviation ER1. However, the OCV 80 is actually in the state shown in FIG. 9B, and both the A port 86 and the B port 87 are closed. Therefore, in this case, the deviation ER1 is not eliminated and remains as a steady deviation. This steady-state error ER1 is given by
It is represented by the following equation.

[0057]

(Equation 5)

Therefore, in the conventional control device,
By adding the integral control to the proportional control of the formula (1) and performing the control expressed by the formula (6), the above-mentioned steady-state error is prevented from remaining.

[0059]

(Equation 6)

In the equation (6), ΣKI is a deviation ER between the target valve timing VTT and the actual valve timing VTA.
Is an integral correction value obtained by integrating the integral increase / decrease value calculated based on the equation (7), and is calculated by the equation (7).

[0061]

(Equation 7)

In the equation (7), ΣKI (i-1) is
This is the integration correction value before the current integration, and KI is a gain corresponding to the integration operation. Also, in the equation of Equation 7, KI ×
ER is equivalent to the integral increase / decrease value, and this KI is determined by the transient increase in the error ER caused by a step response or the like.
The integral correction value ΣKI is set to a very small value so that the control does not become unstable as a result of large fluctuation. The target valve timing VTT and the actual valve timing VTT in a state where no steady-state deviation remains between the target valve timing VTT and the actual valve timing VTA, that is, in a state where the integral correction value ΣKI satisfies the equation 8 as a result of the integral control. FIG. 24 shows the movement of the valve timing VTA and the linear solenoid current CNT.

[0063]

(Equation 8)

Next, a control operation based on the equation (6) will be described with reference to FIG. FIG.
3 shows an operation flow chart of the control program stored in No. 3. This operation flow diagram is based on the CPU 10 of the ECU 100.
The processing is performed every predetermined time, for example, every 25 ms. 25, first, at step S1, the crank angle signal period T, the engine speed NE, and the phase difference time TVT are obtained from the crank angle sensor 6, the cam angle sensor 24, the intake air amount sensor 28, the throttle sensor 27, and the water temperature sensor 12. ,
Intake air amount QA, throttle opening TVO, cooling water temperature TH
An operating state signal of the engine such as W is input.

Next, in step S2, the displacement angle (actual valve timing) VTA of the intake side camshaft 19 with respect to the crankshaft 5 is calculated from the crank angle signal cycle T and the phase difference time TVT according to the equation (2). next,
In step S3, the engine speed NE and the intake air amount Q
A, the target valve timing VTT is calculated based on the throttle opening TVO and the coolant temperature THW. Next, in step S4, a deviation ER between the target valve timing VTT and the actual valve timing VTA is calculated according to the equation (4).

Next, in step S5, an integral correction value ΣKI is obtained according to the equation (7). In this case, ΣKI (i−1) in the equation of Equation 7 indicates ΣKI 25 ms before. Note that the integral correction value は KI is determined by the ECU 10
It is initialized to 0 immediately after power is applied to 0. Next, in step S6, the linear solenoid current CNT of the OCV 80 is obtained according to the equation (6).

Next, at step S7, the timer 10
7, the OCV is output to the output port 108.
A duty signal corresponding to the 80 linear solenoid current CNT is output. This duty signal is input to the current control circuit 114, and is output to the linear solenoid 8 of the OCV 80.
3 is controlled so as to be a linear solenoid current CNT. As a result, the actual valve timing VTA
Is controlled to reach the target valve timing VTT.

[0068]

In the above-described conventional valve timing control apparatus for an internal combustion engine, the state in which the integral correction value ΣKI immediately after power is applied to the ECU 100 is initialized, and the actual holding current HLD of the OCV 80 Changes due to a change in the operating state or the like, a steady-state error occurs between the target valve timing VTT and the actual valve timing VTA. To eliminate the steady-state error in a short time, the gain KI corresponding to the integral operation is reduced. Must be set to a large value. However, when the gain KI corresponding to the integration operation is set to a large value, as shown in FIG. 26, the transient correction ER generated at the time of a step response or the like causes a large change in the integration correction value ΣKI. However, there has been a problem that control becomes unstable, overshoot or hunting occurs in the actual valve timing VTA, convergence to the target valve timing VTT is delayed, and operating performance and exhaust gas deteriorate.

Conversely, if the gain KI corresponding to the integration operation is set to a small value so that the control does not become unstable,
As shown in FIG. 27, the target valve timing which is generated when the integral correction value ΣKI immediately after power is applied to the ECU 100 or when the actual holding current HLD changes due to a change in the operating state or the like. There is a problem that a steady-state deviation between the VTT and the actual valve timing VTA remains for a long period of time, which also causes deterioration of the operation performance and the exhaust gas.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to cause the actual valve timing VTA to stably follow a change in the target valve timing VTT. Even when the integral correction value ΣKI immediately after the power is applied or the actual holding current HLD of the OCV 80 changes due to a change in the operating state, the actual valve timing VTA is set to the target valve timing in a short time. It is an object of the present invention to provide a valve timing control device for an internal combustion engine that can converge to VTT.

[0071]

According to a first aspect of the present invention, an intake passage and an exhaust passage which are driven at a predetermined timing in synchronization with the rotation of an internal combustion engine and communicate with a combustion chamber are provided. An intake valve and an exhaust valve for opening and closing, an operating state detecting means for detecting an operating state of the internal combustion engine, and a target valve for calculating a target valve timing for the operating state of the internal combustion engine based on a detection result of the operating state detecting means Timing calculating means, a variable valve timing mechanism for changing the opening / closing timing of at least one of the intake valve and the exhaust valve, actual valve timing detecting means for detecting the actual valve timing of the valve whose opening / closing timing has been changed, and a target valve The valve timing is based on the value related to the deviation between the timing and the actual valve timing. And the actual valve timing control means for generating a control amount for controlling the grayed variable mechanism, and the integral decrease value calculating means for calculating the integrated variation value based on the value relating to the deviation between the actual valve timing and the target valve timing,
Integral control means for calculating the integral correction value by integrating the integral increase / decrease value to correct the control amount of the variable valve timing mechanism by the actual valve timing control means, and the actual valve timing changes in the direction of the target valve timing. And integration stop means for stopping the integration of the integration control means when the operation is in progress.

According to a second aspect of the present invention, the integration stop means has a change speed determination means for determining whether or not the change speed of the actual valve timing is equal to or higher than a predetermined integration stop determination speed. Is determined to be changing toward the target valve timing at or above the predetermined integration stop determination speed, the integration of the integration control means is stopped.

According to a third aspect of the present invention, the change speed judging means judges the integration stop when the absolute value of the value related to the deviation between the actual valve timing and the target valve timing is smaller than when the absolute value is larger. The speed is set to be small.

According to a fourth aspect of the present invention, the change speed determining means determines whether the absolute value of the value relating to the difference between the actual valve timing and the target valve timing is equal to or greater than a predetermined value and a predetermined period has elapsed. The integration stop determination speed is set to be smaller than that after the lapse of the period.

According to a fifth aspect of the present invention, the change speed judging means sets the absolute value of the value related to the difference between the actual valve timing and the target valve timing to increase until a predetermined period elapses, and then, after the predetermined period elapses. In contrast, the integration stop determination speed is set to be small.

According to a sixth aspect of the present invention, the integral increase / decrease value calculating means sets the integral increase / decrease value when the absolute value of the value related to the deviation between the actual valve timing and the target valve timing is small, as compared to when the absolute value is large. The value is calculated to be small.

According to a seventh aspect of the present invention, the integral increase / decrease value calculating means sets the absolute value of the value relating to the difference between the actual valve timing and the target valve timing to a predetermined value or more until a predetermined period elapses. The integral increase / decrease value is calculated to be smaller than that after a predetermined period has elapsed.

According to an eighth aspect of the present invention, the integral increase / decrease value calculating means sets a predetermined period of time from when the absolute value of the value related to the deviation between the actual valve timing and the target valve timing increases until a predetermined period elapses. The integrated increase / decrease value is calculated to be smaller than later.

According to a ninth aspect of the present invention, the actual valve timing control means controls the variable valve timing mechanism when the absolute value of the value relating to the deviation between the actual valve timing and the target valve timing is less than a predetermined value. Is maintained at a predetermined value.

[0080]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual configuration diagram showing a basic conceptual configuration of the present invention, FIG. 2 is a schematic diagram showing a gasoline engine system having a variable valve timing mechanism according to an embodiment of the present invention, and FIG. FIG. 4 is an explanatory view showing a cross section near the intake-side camshaft provided and a configuration of hydraulic oil supply means for driving and controlling the VVT 40. FIG.
FIG. 5 is an explanatory view showing a state in which hydraulic pressure is applied to FIG.
FIG. 6 is an explanatory view of the cross section taken along line XX in the arrow direction, FIG. 6 is an explanatory view showing a moving state of the slide plate 71, and FIG.
FIG. 8 is an explanatory view of the YY cross section in FIG. 3 viewed from the direction of the arrow.
Is an explanatory view of the ZZ section in FIG. 3 as viewed from the direction of the arrow, FIG. 9 is an explanatory view of a typical operation state of the OCV 80, FIG.
Is a characteristic diagram showing the relationship between the linear solenoid current and the actual valve timing change speed, FIG. 11 is a characteristic diagram showing the variation in the relationship between the linear solenoid current and the actual valve timing change speed, and FIG. FIG. 4 is an operation timing chart showing a phase relationship of a cam angle signal and a method of calculating an actual valve timing VTA. Since the configuration and operation are the same as those described in the section of the prior art,
The description is omitted.

FIG. 13 shows the internal configuration of the ECU 100 shown in FIG.
7, except that the control program and data of the operation flow chart are written, are the same as the contents described in the section of the prior art, and the description thereof will be omitted.

Next, the operation of the valve timing control device for an internal combustion engine according to the embodiment of the present invention will be described with reference to FIGS. FIG. 14 is an operation timing chart showing a control operation in a state where the actual valve timing VTA converges near the target valve timing VTT. The absolute value of the deviation ER between the target valve timing VTT and the actual valve timing VTA is a predetermined value E1 (for example, 1 °
If it is less than CA), it is determined that the actual valve timing has substantially converged to the target valve timing, and the integrated increase / decrease value is set to a value KI1 (for example, 0. 1 mA).
However, when the actual valve timing VTA is slightly moving toward the target valve timing VTT, it is not necessary to further increase or decrease the integral correction value ΣKI.
When moving toward the target valve timing at a speed of (for example, 0.01 ° CA / 25 ms) or more, the integration of the integral increase / decrease value is stopped.

FIG. 15 is an operation timing chart showing a control operation in a state where a steady deviation occurs between the actual valve timing VTA and the target valve timing VTT.
Target valve timing VTT and actual valve timing VT
When the absolute value of the deviation ER of A is equal to or greater than a predetermined value E1 and the actual valve timing VTA is not moving at a speed equal to or greater than a predetermined integration stop determination speed toward the target valve timing VTT, the target valve timing VTT In order to judge that a steady-state error has occurred between the actual valve timing VTA and to rapidly control the steady-state error to be eliminated, the integral increase / decrease value is set to a value KI2 (for example, 1 mA) larger than the above-mentioned KI1. I do. Here, if the predetermined integration stop determination speed remains at V1, no matter how large the integration increase / decrease value is, when the change speed of the actual valve timing VTA becomes V1 or more, the integration increase / decrease value is integrated. Stops, the change speed of the actual valve timing VTA does not become higher than V1. Therefore, the absolute value of the deviation ER is equal to the predetermined value E1.
In the above case, the integration stop determination speed is set to a value V2 (for example, 0.1 ° C.) larger than V1 in accordance with the increase of the integration increase / decrease value.
A / 25 ms), the actual valve timing VTA can approach the target valve timing at the speed V2.

FIG. 16 is an operation timing chart showing a control operation at the time of a step response in a state where the integral correction value is stable. As shown in this figure, the target valve timing VTT
After the change, the actual valve timing VTA may not move or move slowly for a while due to a delay in transmission of hydraulic oil. In this state, the target valve timing VT
Since the absolute value of the deviation ER between T and the actual valve timing VTA is equal to or greater than the predetermined value E1,
It is erroneously determined that a steady-state error has occurred, and
Since the integration stop determination speed is set to V2 in I2, the integration correction value ΣKI, which does not need to be increased or decreased, is increased or decreased. Then, after the absolute value of the deviation ER has changed from less than the predetermined value E1 to the predetermined value E1 or more, during a predetermined time TD (for example, 0.2 sec), the same as when the absolute value of the deviation ER is less than the predetermined value E1. Then, the integration increase / decrease value is set to KI1, and the integration stop determination speed is set to V1.

Thus, the target valve timing VTT
After the change in the actual valve timing VTA, the increase / decrease of the integral correction value ΣKI in a state where the actual valve timing VTA has not yet moved can be suppressed slightly, and even if the actual valve timing VTA is slight, it can be moved toward the target valve timing VTT. For example, to stop the integration of the integral increase / decrease value, the integral correction value Σ
KI hardly fluctuates. After the elapse of the predetermined time TD, the actual valve timing VTA is already V2
Since the moving speed is moving toward the target valve timing VTT at the above changing speed, the integration of the integral increase / decrease value is stopped also at this time. Further, when the actual valve timing VTA approaches the target valve timing VTT, the change speed decreases. However, when the deviation ER from the target valve timing VTT enters a region less than the predetermined value E1, the integration stop determination speed becomes V1.
In addition, since the integral increase / decrease value becomes a small value for KI1, the integral correction value ΣKI does not unnecessarily increase / decrease at this time, and the actual valve timing VTA converges stably to the target valve timing VTT.

The above operation will be described with reference to the operation flowchart of FIG. FIG. 17 is a diagram showing the operation of the conventional device.
25 is replaced with steps S10 to S26, and the same steps as those in FIG. 25 are denoted by the same step numbers, and detailed description thereof will be omitted. The operation flow chart of FIG.
Is processed every 25 ms.

In FIG. 17, first, at step S1, the crank angle signal cycle T, the engine speed NE, the phase difference time TVT, the intake air amount QA, the throttle opening TVO, the cooling water temperature THW are obtained from various sensors as the operating state detecting means. And various operating state signals of the engine 1 as an internal combustion engine. Next, the actual valve timing VTA is calculated in step S2 as actual valve timing detecting means. Next, in step S3, a target valve timing VTT is calculated based on the engine speed NE, the intake air amount QA, the throttle opening TVO, the cooling water temperature THW, etc. obtained in step S1. Here, step 3 constitutes a target valve timing calculating means. Next, in step S4, a deviation ER between the target valve timing VTT and the actual valve timing VTA is calculated as a value related to the deviation between the target valve timing and the actual valve timing according to the equation (4). Steps S1 to S4 are the same processes as those of the conventional apparatus shown in FIG.

Next, at step S10, it is determined whether or not the absolute value of the deviation ER is less than a predetermined value E1, and if it is determined that the absolute value of the deviation ER is less than the predetermined value E1, then at step S11. , Reset the timer TM to the initial value 0. On the other hand, in step S10, the absolute value of the deviation ER is
If it is determined that it is equal to or greater than R1, the timer TM is incremented by one in step S12. As a result of the processing in steps S10 to S12, the timer TM measures the predetermined period, and the elapsed time after the absolute value of the deviation ER has changed from less than the predetermined value E1 to not less than the predetermined value E1 (1 LSB = 25 ms) Is represented.

After the end of step S11 or step S12, in step S13, the actual valve timing V
The value obtained by subtracting the actual valve timing VTAB 25 ms before from TA is stored in ΔVT, and then the actual valve timing VT of this time is added to the actual valve timing VTAB 25 ms before.
A is stored. Here, ΔVT represents a change amount of the actual valve timing VTA during 25 ms, that is, a change speed.

Next, in step S14, the deviation ER becomes zero.
When it is determined whether or not the difference is greater than or equal to 0, that is, when it is determined that the actual valve timing VTA is on the retard side of the target valve timing VTT, the process proceeds to step S15. In step S15, it is determined whether the absolute value of the deviation ER is smaller than a predetermined value E1.
If it is determined that it is less than 1, the process proceeds to step S17. In step S15, the absolute value of the deviation ER is E
If it is determined that the value is equal to or more than 1, the process proceeds to step S16, and it is determined whether the timer TM is less than 8.
The elapsed time from when the value is less than 1 to a value equal to or more than the predetermined value E1 is 0.0.
If it is determined that the time is less than 2 sec (25 ms × 8), the process proceeds to step S17.

In step S17, the change speed ΔVT is V
If the change speed ΔVT is less than V1, it is determined whether the actual valve timing VTA is moving toward the target valve timing VTT at a speed less than V1 / 25 ms, or Valve timing V
Since it can be determined that TA is moving away from the target valve timing VTT, in step S18, a predetermined value KI1 is added to the integral correction value ΣKI, and the process proceeds to step S6. If it is determined in step S17 that the change speed ΔVT is equal to or higher than V1, it can be determined that the actual valve timing VTA is moving toward the target valve timing VTT at a speed equal to or higher than V1 / 25 ms, and the process of step S18 is performed. Instead, the process proceeds to step S6.

On the other hand, in step S16, the elapsed time after the timer TM becomes 8 or more, that is, the absolute value of the deviation ER becomes less than the predetermined value E1 and becomes more than the predetermined value E1 is 0.2 seconds.
If it is determined that it is not less than c, the process proceeds to step S19. In step S19, it is determined whether or not the change speed ΔVT is equal to or higher than V2. If it is determined that the change speed ΔVT is lower than V2, the actual valve timing VTA is shifted toward the target valve timing VTT by a speed lower than V2 / 25 ms. Or the actual valve timing VTA is moving in a direction away from the target valve timing VTT. Therefore, in step S20, the integral correction value Σ
A predetermined value KI2 is added to KI, and the process proceeds to step S6. If it is determined in step S19 that the change speed ΔVT is equal to or higher than V2, it can be determined that the actual valve timing VTA is moving toward the target valve timing VTT at a speed equal to or higher than V2 / 25 ms, so the process of step S20 is performed. Instead, the process proceeds to step S6. Here, step S17 and step S19 are a change speed determination means and an integration stop means,
Steps S18 and S20 are integration increase / decrease value calculation means and integration control means, V1 and V2 are integration stop determination speeds, K
I1 and KI2 each constitute an integral increase / decrease value.

In step S14, the deviation ER is less than 0,
That is, when it is determined that the actual valve timing VTA is on the advance side of the target valve timing VTT, the process proceeds to step S21. In step S21, it is determined whether or not the absolute value of the deviation ER is less than a predetermined value E1, and if it is determined that the absolute value of the deviation ER is less than the predetermined value E1, the process proceeds to step S23. If it is determined in step S21 that the absolute value of the deviation ER is equal to or larger than E1, the process proceeds to step S21.
Then, it is determined whether or not the timer TM is less than 8, and the elapsed time after the timer TM is less than 8, that is, the absolute value of the deviation ER is changed from less than the predetermined value E1 to not less than the predetermined value E1 is set to 0. If it is determined that the time is less than .2 seconds, the process proceeds to step S23.

In the step S23, the change speed ΔVT becomes −
V1 or less, and if it is determined that the change speed ΔVT is greater than −V1, the actual valve timing VTA
Becomes V1 / 25 toward the target valve timing VTT.
ms, or it can be determined that the actual valve timing VTA is moving in a direction away from the target valve timing VTT. In step S24, the predetermined value KI1 is subtracted from the integral correction value ΣKI. Proceed to S6. If it is determined in step S23 that the change speed ΔVT is equal to or less than -V1, the actual valve timing VT
A moves toward the target valve timing VTT, V1 / 2
Since it can be determined that the vehicle is moving at a speed of 5 ms or more, the process proceeds to step S6 without performing the process of step S24.

On the other hand, in step S22, the elapsed time after the timer TM becomes 8 or more, that is, the absolute value of the deviation ER becomes less than the predetermined value E1 and becomes more than the predetermined value E1 is 0.2 seconds.
If it is determined that it is equal to or greater than c, the process proceeds to step S25. In step S25, it is determined whether or not the change speed ΔVT is equal to or less than −V2. If it is determined that the change speed ΔVT is larger than −V2, the actual valve timing VTA is less than V2 / 25 ms toward the target valve timing VTT. Moving at the speed of the actual or the actual valve timing VT
Since it can be determined that A is moving away from the target valve timing VTT, a predetermined value KI2 is subtracted from the integral correction value ΣKI in step S26, and the process proceeds to step S6. If it is determined in step S25 that the change speed ΔVT is equal to or less than −V2, it can be determined that the actual valve timing VTA is moving toward the target valve timing VTT at a speed of V2 / 25 ms or more.
The process proceeds to step S6 without performing the process of. Here, step S23 and step S25 are change speed determination means and integration stop means, step S24 and step S26 are integration increase / decrease value calculation means and integration control means, -V1 and -V2 are integration stop determination speeds, -KI1 and -KI2. Each constitute an integral increase / decrease value.

After calculating the integral correction value ΣKI in the above steps S10 to S26, in step S6, the linear solenoid current CNT of the OCV 80 is obtained according to the equation (6). Step S6 includes actual valve timing control means, and adds (KP × ER + 0.5A) as a control amount obtained from the actual valve timing control means and ΣKI as an integral correction value obtained from the integral control means. Thus, the linear solenoid current CNT is obtained. Next, in step S7, a duty signal corresponding to the linear solenoid current CNT of the OCV 80 is output to the output port 108. Steps S6 and S7
Is the same process as the step of the conventional device shown in FIG.

Embodiment 2 In the first embodiment, one of the two values KI1 and KI2 is selected as the integral increase / decrease value depending on whether or not the deviation ER is equal to or more than the predetermined value E1. In addition, the integration stop determination speed is also determined by whether the deviation ER is equal to or greater than E1 and is one of two values of V1 and V2.
One to choose. Further, since the deviation ER is changed from less than E1 to E1 or more, it is predicted that the actual valve timing VTA may not change for a while after that despite the increase in the deviation ER.
During the time period TD after the value becomes less than E1 or more, KI1 is selected as the integration increase / decrease value, and V1 is selected as the integration stop determination speed. Even with such simple integration increase / decrease value switching, integration stop determination speed switching, and deviation increase determination, the object of the present invention can be sufficiently achieved.
Of course, as shown in FIGS.
It is also possible to continuously change the integration stop determination speed and the deviation increase determination timing based on the deviation ER.

FIG. 18 shows the deviation ER and the deviation ER for integral control.
FIG. 3B is an operation timing chart showing the operation of the timer TM and the timer TM. The integral control deviation ERB is created based on the deviation ER. When the absolute value of the deviation ER between the target valve timing VTT and the actual valve timing VTA increases due to a change in the operating state of the internal combustion engine or the like. After that, for 0.2 seconds, for example, the deviation ER before the deviation ER increases is retained in the deviation ERB for integral control. In other cases, the integral control deviation ERB has a value equal to the deviation ER. The integral control deviation ERB is a value related to the deviation between the target valve timing and the actual valve timing.

Next, VM (ERB) is an integration stop judging speed, which is a value that continuously changes in accordance with the integration control deviation ERB as shown in FIG. Is stored. Here, when the deviation ERB for integration control is 0 or more, VM (ERB) becomes a positive value, and when the deviation ERB is less than 0, VM (ERB)
RB) is set to be a negative value. Further, as the absolute value of the integral control deviation ERB is larger, the VM (ER
Since the absolute value of B) is set to be large, and the value can be set freely according to the characteristics of the control device, the control accuracy can be increased.

KIM (ERB) is an integral increase / decrease value, for example, an integral control deviation E as shown in FIG.
This is a value that continuously changes according to the RB, and is stored in the ROM 103 in advance as a map value. Here, when the deviation ERB for integration control is 0 or more, KIM (ERB) becomes a positive value, and when the deviation ERB is less than 0, KIM (ERB) becomes KIM (ERB).
(ERB) is set to be a negative value. Also, the larger the absolute value of the integral control deviation ERB, the larger the KI
Since the absolute value of M (ERB) is set to be large, and the value can be set freely according to the characteristics of the control device, control accuracy can be improved.

That is, in the second embodiment, the deviation ER
Is used, the deviation ERB for integration control is used. As described above, the integral control deviation ERB retains the value at that time for a predetermined time even if the deviation ER changes. That is, after the target valve timing VTT changes due to a change in the operating state, the actual valve timing VT changes due to a delay in the transmission of hydraulic oil.
Even if the deviation ER increases due to the poor movement of A, the integration control deviation ERB does not change for a predetermined time, so that the integration correction value ΣKI does not needlessly change. Note that, as shown in FIG. 18, the measurement is started at an arbitrary point in time when the deviation ER has increased for the predetermined time 0.2 sec. Therefore, it is possible to arbitrarily change the deviation increase determination timing.

Next, 0.2 seconds after the deviation ER increases.
After elapse, the deviation ERB for integration control becomes the deviation E at that time.
Given the value of R. The control device performs an integration stop determination speed VM based on the calculated value of the integration control deviation ERB.
(ERB) and integral increase / decrease value KIM (ERB) in ROM1
Read from 03. And the actual valve timing VTA
Is determined to be equal to or higher than the integration stop determination speed VM (ERB) read out above. When the deviation ER is positive and the change speed ΔVT is equal to or higher than the integration stop speed VM (ERB), or when the deviation ER is negative and the change speed ΔVT is equal to or lower than the integration stop speed VM (ERB), the target valve timing is set to a sufficient speed. Since the VTT is approaching VTT, the integration operation is stopped. Conversely, when the deviation ER is positive and the change speed ΔVT is lower than the integral stop speed VM (ERB), or when the deviation ER is negative and the change speed ΔVT is higher than the integral stop speed VM (ERB), the target valve timing VTT , Or moving in a direction away from the target valve timing VTT, the integration is performed based on the integration control deviation ERB. The integral increase / decrease value at this time is obtained by reading the KIM (ERB) from the ROM 103, and as shown in FIG.
The value increases as the RB increases. Therefore,
The larger the integral control deviation ERB, the larger the actual valve timing VTA and the target valve timing VT with a larger integral gain.
When the actual valve timing VTA approaches the target valve timing VTT as well as approaching T, the integral gain is gradually reduced, and converges to the target valve timing VTT quickly and stably.

Next, the second embodiment will be described in detail with reference to the operation flowchart of FIG. FIG. 21 is a flowchart of the operation of the first embodiment, in which Steps S10 to S12 are replaced with Steps S30 to S34, and Steps S15 to S26 are replaced with Steps S35 to S37, respectively. The same steps as those in FIG. 17 are denoted by the same step symbols, and detailed description thereof will be omitted. The operation flow chart of FIG. 21 is processed in the CPU 102 every 25 ms.

In FIG. 21, after the deviation ER between the target valve timing VTT and the actual valve timing VTA is determined in step S4, it is determined in step S30 whether the absolute value of the deviation ER is equal to or less than the absolute value of the integral control deviation ERB. Determine whether or not. If it is determined in step S30 that the absolute value of the deviation ER is equal to or smaller than the absolute value of the integral control deviation ERB, the timer TM is reset to 0 in step S31, and further, in step S32, Deviation ERB for integral control
Is stored, and the process proceeds to step S13. On the other hand, if it is determined in step S30 that the absolute value of the deviation ER is larger than the absolute value of the integral control deviation ERB, it is determined that the deviation ER has increased, and the timer TM is incremented by one. Further, in step S34, the timer TM
Is greater than or equal to 8, that is, 0.2
It is determined whether or not a predetermined period has elapsed since the timer TM has counted 8 or more, that is, the deviation has increased.
If it is determined that 2 seconds or more have elapsed, step S3
Proceeding to 1, the timer TM is reset to 0, and in step S32, the deviation ER is stored in the deviation ERB for integration control. When it is determined in step S34 that the timer TM is less than 8, that is, the elapsed time after the increase in the deviation is less than 0.2 sec, the process proceeds to step S13.

Next, at step S13, after the change speed ΔVT of the actual valve timing VTA is obtained,
At 14, it is determined whether the deviation ER is equal to or greater than 0, and the deviation ER is determined.
Is determined to be 0 or more, the process proceeds to step S35. In step S35, it is determined whether or not the change speed ΔVT is equal to or higher than VM (ERB). If it is determined that the change speed ΔVT is lower than VM (ERB), the actual valve timing VTA is determined.
Becomes VM / 25 toward the target valve timing VTT.
Since it can be determined that the valve is moving at a speed less than ms or the actual valve timing VTA is moving in a direction away from the target valve timing VTT, the process proceeds to step S37, and a predetermined value KIM (ERB) is added to the integral correction value ΣKI. Then, the process proceeds to step S6. If it is determined in step S14 that the change speed ΔVT is equal to or greater than VM (ERB), it can be determined that the actual valve timing VTA is moving toward the target valve timing VTT at a speed equal to or greater than VM / 25 ms. The process proceeds to step S6 without performing the process in step S37.

On the other hand, in step S14, deviation ER is set to 0.
If it is determined that the change speed ΔVT is less than VM (ERB), it is determined whether or not the change speed ΔVT is equal to or less than VM (ERB). Since it can be determined that the target valve timing VTT is moving at a speed of less than -VM / 25 ms or that the actual valve timing VTA is moving away from the target valve timing VTT, the process proceeds to step S37, where the integral correction is performed. Value ΣKI
Is added to the predetermined value KIM (ERB), and the process proceeds to step S6. In step S14, the change speed ΔVT is set to VM (ER
B) If it is determined to be less than or equal to, the actual valve timing VTA is shifted toward the target valve timing VTT by -V
Since it can be determined that the vehicle is moving at a speed of M / 25 ms or more, the process proceeds to step S6 without performing the process of step S37. Here, steps S35 and S36 constitute a change speed determining means and an integration stopping means, and step S37 constitutes an integral increase / decrease value calculating means and an integral control means, respectively.

By the above steps, the integral correction value ΣKI
, The linear solenoid current CNT of the OCV 80 is obtained in step S6 in accordance with the equation (6), as in the first embodiment.
At 08, a duty signal corresponding to the linear solenoid current CNT of the OCV 80 is output.

It should be noted that Embodiments 1 and 2 described above are used.
In the above, the integration operation is stopped when the actual valve timing VTA is moving toward the target valve timing VTT at a predetermined speed or higher. However, as another embodiment, for example, regardless of the speed at which the actual valve timing VTA moves toward the target valve timing VTT, the integration operation is prohibited when the actual valve timing VTA moves toward the target valve timing VTT. good.

In the first and second embodiments, the deviation ER or the integration control deviation ERB is not increased until the predetermined period of time 0.2 seconds elapses after the deviation ER or the integration control deviation ERB increases. ERB was kept at a predetermined value. However, the embodiment is not limited to this, and the deviation ER or the integration control deviation ERB may be calculated so as to be smaller after the predetermined period elapses until the predetermined period elapses. In the first and second embodiments, the predetermined period is 0.2 seconds.
Although c is used, this value may be arbitrarily changed. Further, the predetermined periods of the first embodiment and the second embodiment may be different from each other.

In the first and second embodiments, the feedback control is performed by the proportional control and the integral control. However, as described in Japanese Patent Application Laid-Open No. 6-159021, differential control is added. You may. Also,
In the above embodiment, the proportional control is always executed.
When the value related to the deviation such as the deviation ER or the integral control deviation ERB is less than a predetermined value (for example, 1 ° CA), the proportional control may be prohibited and only the integral control may be performed. That is, when the value related to the deviation becomes smaller than the predetermined value, the proportional control amount at that time is set to zero, and the actual valve timing converges to the target valve timing only by the integral control. Also,
In the above-described embodiment, the mechanism in which the variable valve timing mechanism body rotates with the rotation of the timing pulley has been described. However, the variable valve timing mechanism body described in Japanese Patent Application No. 8-267603 does not rotate. The present invention is also applicable to a mechanism of a system or a system in which an actual valve timing is detected by a potentiometer.

[0111]

As described above, according to the first aspect of the invention, when the actual valve timing is moving in the direction of the target valve timing, the integration of the integration increase / decrease value by the integration control means is stopped. I do. As a result, the actual valve timing can be stably converged toward the target valve timing. On the other hand, in a state where a steady-state deviation occurs between the actual valve timing and the target valve timing, the integral control means executes the integration of the integral increase / decrease value, so that the steady-state deviation can be eliminated.

According to the second aspect of the invention, when the actual valve timing is moving at a speed equal to or higher than the predetermined integration stop determination speed in the direction of the target valve timing, the integration control means integrates the integration increase / decrease value. To stop. As a result, even if the target valve timing changes and the value related to the deviation between the actual valve timing and the target valve timing transiently increases, the actual valve timing changes at a speed higher than the predetermined integration stop determination speed at this time. Since the integration of the integral increase / decrease value is stopped, the actual valve timing can be stably converged toward the target valve timing without unnecessarily increasing / decreasing the integral correction value.

According to the third aspect of the invention, when the absolute value of the value related to the difference between the actual valve timing and the target valve timing is small, the integration stop determination speed is reduced as compared to when the absolute value is large. Since the actual valve timing is set to a small value, the actual valve timing can stably converge to the target valve timing when the actual valve timing is near the target valve timing.

According to the fourth aspect of the present invention, a predetermined period elapses from when the absolute value of the value relating to the deviation between the actual valve timing and the target valve timing becomes equal to or more than a predetermined value until a predetermined period elapses. Later, the integration stop determination speed is set smaller. Therefore, even if the target valve timing changes and the absolute value of the value related to the difference between the actual valve timing and the target valve timing becomes equal to or more than the predetermined value, the value related to the deviation is large until the predetermined period elapses. Nevertheless, since the integration stop determination speed is set to a small value, the integral correction value slightly increases or decreases, and the actual valve timing can be stably converged toward the target valve timing.

Further, according to the fifth aspect of the present invention, it is necessary to increase the absolute value of the value related to the difference between the actual valve timing and the target valve timing until a predetermined period elapses. Set the integration stop judgment speed to a low value. Therefore, the deviation increase determination timing can be arbitrarily changed.

According to the present invention, when the absolute value of the value related to the deviation between the actual valve timing and the target valve timing is small, the integral increase / decrease value is smaller than when the absolute value is large. calculate. Therefore, when the actual valve timing is in the vicinity of the target valve timing, the integral correction value fluctuates only slightly, and the actual valve timing converges stably to the target valve timing.

Further, according to the present invention, a predetermined period elapses until a predetermined period elapses after an absolute value of a value relating to a deviation between the actual valve timing and the target valve timing becomes a predetermined value or more. Later, the integrated increase / decrease value is calculated smaller. Therefore, even if the target valve timing changes and the absolute value of the value related to the difference between the actual valve timing and the target valve timing becomes equal to or more than the predetermined value, the value related to the deviation is large until the predetermined period elapses. Nevertheless, since the integral increase / decrease value is calculated to be small, the integral correction value only slightly increases / decreases, and the actual valve timing can be stably converged toward the target valve timing.

Further, according to the present invention, it is possible to increase the absolute value of the value related to the difference between the actual valve timing and the target valve timing until a predetermined period elapses, and to compare the absolute value of the value after the predetermined period elapses. Calculate the integral increase / decrease value to be small. Therefore, the deviation increase determination timing can be arbitrarily changed.

According to the ninth aspect of the present invention, when the absolute value of the value related to the deviation between the actual valve timing and the target valve timing is less than a predetermined value, the control amount for controlling the variable valve timing mechanism is provided. Is maintained at a predetermined value.
Therefore, when the actual valve timing is in the vicinity of the target valve timing, the control amount of the actual valve timing control means is held, and the actual valve timing is changed by the integration control means. Can be controlled.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram showing a basic conceptual configuration of the present invention.

FIG. 2 is a schematic diagram showing a gasoline engine system having a variable valve timing mechanism according to Embodiments 1 and 2 of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a variable valve timing mechanism and hydraulic oil supply means for driving and controlling the variable valve timing mechanism according to Embodiments 1 and 2 of the present invention.

FIG. 4 is an operation explanatory diagram according to FIG. 3;

FIG. 5 is a sectional view taken along line XX of FIG. 3;

FIG. 6 is an explanatory diagram showing a moving state of the slide plate according to the first and second embodiments of the present invention.

FIG. 7 is a sectional view taken along line YY of FIG. 3;

FIG. 8 is a sectional view taken along the line ZZ in FIG. 3;

FIG. 9 is an operation explanatory diagram of the oil control valve according to the first and second embodiments of the present invention.

FIG. 10 is a characteristic diagram illustrating a relationship between a linear solenoid current and an actual valve timing change speed according to the first and second embodiments of the present invention.

FIG. 11 is a characteristic diagram illustrating a variation in a relationship between a linear solenoid current and an actual valve timing change speed according to the first and second embodiments of the present invention.

FIG. 12 is an operation timing chart showing an example of a crank angle signal, a cam angle signal, and actual valve timing according to the first and second embodiments of the present invention.

FIG. 13 is a configuration diagram showing an internal configuration of an electronic control unit according to Embodiments 1 and 2 of the present invention.

FIG. 14 is an operation timing chart for explaining the operation according to the first embodiment of the present invention;

FIG. 15 is an operation timing chart for explaining the operation according to the first embodiment of the present invention;

FIG. 16 is an operation timing chart for explaining the operation according to the first embodiment of the present invention;

FIG. 17 is an operation flowchart showing an operation of the first embodiment of the present invention.

FIG. 18 is an operation timing chart for explaining an operation according to the second embodiment of the present invention.

FIG. 19 is a diagram showing a relationship between an integration control deviation ERB and an integration stop determination speed VM (ERB) according to the second embodiment of the present invention.

FIG. 20 is a diagram showing a relationship between the integral control deviation ERB and the integral increase / decrease value KIM (ERB) according to the second embodiment of the present invention.

FIG. 21 is an operation flowchart showing an operation of the second embodiment of the present invention.

FIG. 22 is an operation timing chart showing an example of the operation of the conventional device.

FIG. 23 is an operation timing chart showing an example of the operation of the conventional device.

FIG. 24 is an operation timing chart showing an example of the operation of the conventional device.

FIG. 25 is an operation flowchart showing the operation of the conventional device.

FIG. 26 is an operation timing chart for explaining a problem of the conventional device.

FIG. 27 is an operation timing chart for explaining a problem of the conventional device.

[Explanation of symbols]

M1 internal combustion engine, M2 combustion chamber, M3 intake passage, M4
Exhaust passage, M5 intake valve, M6 exhaust valve, M
7 Operating state detecting means, M8 Target valve timing calculating means, M9 Variable valve timing mechanism, M10 Fluid supply means, M11 Actual valve timing detecting means, M
12 actual valve timing control means, M13 integral increase / decrease value calculation means, M14 integral control means, M15 integration stop means, 1 engine, 6 crank angle sensor, 8 combustion chamber, 12 water temperature sensor 15 intake passage, 16 exhaust passage, 17 intake valve ,
18 Exhaust valve 24 Cam angle sensor, 27 Throttle sensor, 28
Intake air amount sensor 40 Variable valve timing mechanism (VVT) 80 Oil control valve (OCV) 100 Electronic control unit (ECU)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 13/02-45/00 F01L 1/34-13/00

Claims (9)

(57) [Claims] An intake valve and an exhaust valve which are driven at a predetermined timing in synchronization with the rotation of the internal combustion engine to open and close an intake passage and an exhaust passage leading to a combustion chamber, respectively;
Operating state detecting means for detecting an operating state of the internal combustion engine; target valve timing calculating means for calculating a target valve timing for the operating state of the internal combustion engine based on a detection result of the operating state detecting means; Alternatively, a valve timing variable mechanism that changes the opening / closing timing of at least one of the exhaust valves; actual valve timing detecting means that detects the actual valve timing of the valve whose opening / closing timing has been changed; Actual valve timing control means for generating a control amount for controlling the variable valve timing mechanism based on a value related to a deviation from the valve timing, a value related to a deviation between the actual valve timing and the target valve timing Integration that calculates the integral increase / decrease value based on Increase / decrease value calculation means; integration control means for integrating the integral increase / decrease value to calculate an integral correction value for correcting the control amount of the variable valve timing mechanism by the actual valve timing control means; A valve timing control device for an internal combustion engine, comprising: integration stop means for stopping the integration of the integration control means when the value is changing in the direction of the target valve timing. 2. The integration stop means has a change speed determination means for determining whether or not the change speed of the actual valve timing is equal to or higher than a predetermined integration stop determination speed, and the actual valve timing is determined by a predetermined integration stop determination. 2. The integration control means stops the integration when it is determined that the speed is changing toward the target valve timing at a speed higher than the speed.
A valve timing control device for an internal combustion engine according to any one of the preceding claims. 3. The change speed judging means sets an integral stop judging speed smaller when the absolute value of the value related to the difference between the actual valve timing and the target valve timing is smaller than when the absolute value is larger. 3. The method according to claim 2, wherein
A valve timing control device for an internal combustion engine according to any one of the preceding claims. 4. The change speed determining means stops integration after a lapse of a predetermined period until the lapse of a predetermined period after an absolute value of a value relating to a deviation between the actual valve timing and the target valve timing becomes equal to or more than a predetermined value. 4. The valve timing control device for an internal combustion engine according to claim 3, wherein the determination speed is set to be small. 5. The change speed determination means determines the integration stop determination speed as compared with the predetermined period after the predetermined period elapses after the absolute value of the value related to the difference between the actual valve timing and the target valve timing increases. The valve timing control device for an internal combustion engine according to claim 3, wherein the valve timing control device is set to a small value. 6. An integrated increase / decrease value calculating means, when an absolute value of a value related to a difference between the actual valve timing and the target valve timing is small, calculates an integral increase / decrease value smaller than when the absolute value is large. The valve timing control device for an internal combustion engine according to claim 1, wherein: 7. An integrated increase / decrease value calculating means, wherein the absolute value of the value related to the difference between the actual valve timing and the target valve timing is equal to or greater than a predetermined value and a predetermined period is elapsed.
7. The valve timing control device for an internal combustion engine according to claim 6, wherein the integrated increase / decrease value is calculated to be smaller than after a predetermined period has elapsed. 8. An integral increase / decrease value calculating means for comparing an integral increase / decrease value with respect to a predetermined period until a predetermined period elapses after an absolute value of a value related to a deviation between the actual valve timing and the target valve timing increases. 7. The valve timing control device for an internal combustion engine according to claim 6, wherein the value is calculated to be small. 9. An actual valve timing control means, when an absolute value of a value related to a deviation between the actual valve timing and the target valve timing is less than a predetermined value, sets a control amount for controlling the variable valve timing mechanism to a predetermined value. The valve timing control device for an internal combustion engine according to claim 1, wherein